IMS Roaming Authorization Using Centralized HSS Country Checks

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Solution Overview

Problem

Existing wireless communication systems fail to efficiently manage international IP multimedia system (IMS) roaming, leading to network congestion and unfair cost distribution among subscribers with different service plans, and manual updates of roaming lists are prone to errors.

Innovation Solution

A centralized node architecture for home subscriber servers (HSS) allows a single command to update international roaming lists across multiple HSS databases, coupled with country-specific checks for both network compatibility and subscriber plans, ensuring efficient and error-free authorization of IMS calls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual updates of roaming lists are performed in each HSS database separately, then each database can be updated independently, but this process is prone to errors and is time-consuming

Engineering Contradiction:

Improveaccuracy of roaming list updatesVSAvoidtime required for updating roaming lists

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges multiple HSS database update operations into a single centralized update process. The system maintains a master roaming list that is automatically distributed to all HSS databases simultaneously, eliminating the need for manual separate updates and ensuring consistency across all databases.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The system pre-generates and stores roaming lists in a centralized repository before they are needed by individual HSS databases. This preliminary preparation allows for rapid distribution and automatic updating of all HSS databases without manual intervention during the actual update process.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If international roaming is allowed for all subscribers regardless of service plan, then network coverage is maximized, but cost distribution becomes unfair among subscribers

Engineering Contradiction:

Improveroaming coverage availabilityVSAvoidfairness of cost distribution

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies different authorization rules to different subscriber groups based on their service plans. The system checks the subscriber's specific plan characteristics and applies appropriate roaming policies, allowing some subscribers full international access while restricting others based on their contractual agreements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The roaming authorization system dynamically adjusts access rights based on real-time subscriber plan verification. The system can modify authorization levels during operation depending on the subscriber's service plan type, enabling flexible cost management while maintaining network coverage.

Inventive Principle:

Principle #15Dynamics

3Reliability

If centralized control of roaming authorization is implemented, then cost distribution and authorization accuracy improve, but system complexity increases

Engineering Contradiction:

Improveauthorization accuracyVSAvoidsystem architecture complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal centralized HSS database that serves multiple functions: storing roaming lists, authenticating subscribers, authorizing international access, and distributing authorization data to all network nodes. This multi-functional approach consolidates complexity into a single system rather than distributing it across multiple specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The centralized HSS database acts as an intermediary between the network core and individual HSS databases. It receives service plan definitions from the service provider and translates them into authorization decisions, mediating between complex business rules and simple execution at the network edge.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12598453B2International internet protocol multimedia subsystem (IMS) call network authorization

Publication Date: 2026.04.07 T MOBILE INNOVATIONS LLC

AI summary

A method of authorizing an IMS call in a foreign country for a wireless communication device that has a wireless communication subscription service with a US wireless communication service provider. The method comprises receiving a request to originate an IMS call by a HSS located in the US, wherein the request is received from a first wireless communication device located outside of the US and the request identifies a first country; determining by the HSS that international IMS roaming service is allowed by the wireless communication service provider in the first country; determining by the HSS that a first wireless communication subscription service associated with the first wireless communication device allows international IMS roaming service; and sending an authorization to originate the IMS call by the HSS to the first wireless communication device, whereby the first wireless communication device is enabled to originate the IMS call in the first country.